Azeotrope compositions of octafluorocyclobutane and uses thereof

Abstract

The present disclosure related to azeotrope and near-azeotrope compositions comprising PFC-C318 and HFC-236cb. The present disclosure further relates to processes for removing PFC-C318 from HFC-236cb. And the present disclosure further relates to azeotrope and near azeotrope compositions comprising hydrogen fluoride and PFC-C318.

1. An azeotrope or near-azeotrope composition comprising from about 62.3 mole percent to about 71.3 mole percent PFC-C318 and from about 37.7 mole percent to about 28.7 mole percent HFC-236cb. 
     
     
       2. The azeotrope or near-azeotrope composition of  claim 1 , wherein the vapor pressure of said composition is from about 1.68 psi (11.6 kPa) to about 378 psi (2606 kPa) at a temperature of from about −50° C. to about 110° C. 
     
     
       3. The azeotrope or near-azeotrope composition of  claim 1  wherein said composition consists essentially of from about 62.3 mole percent to about 71.3 mole percent PFC-C318 and from about 37.7 mole percent to about 28.7 mole percent HFC-236cb, wherein the vapor pressure is from about 1.68 psi (11.6 kPa) to about 378 psi (2606 kPa) at a temperature of from about −50° C. to about 110° C. 
     
     
       4. A process for the removal of PFC-C318 from a mixture comprising HFC-236cb and PFC-C318, said process comprising:
 a) subjecting said mixture comprising HFC-236cb and PFC-C318 to a distillation step; and 
 b) removing as distillate a composition comprising an azeotrope or near-azeotrope composition comprising from about 62.3 mole percent to about 71.3 mole percent HFC-236cb and from about 37.7 mole percent to about 28.7 mole percent PFC-C318. 
 
     
     
       5. A process for the separation of PFC-C318 from a mixture comprising HFC-236cb and PFC-C318, said process comprising:
 a) subjecting said mixture to a first distillation step in which a composition enriched in either (i) PFC-C318 or (ii) HFC-236cb is removed as a first distillate composition comprising an azeotrope or near-azeotrope composition comprising from about 62.3 mole percent to about 71.3 mole percent HFC-236cb and from about 37.7 mole percent to about 28.7 mole percent PFC-C318, with a first bottoms composition being enriched in the other of said components (i) or (ii); and 
 b) subjecting said first distillate composition to a second distillation step conducted at a different pressure than the first distillation step in which the component enriched as first bottoms composition in (a) is removed in a second distillate composition with a second bottoms composition enriched in the same component which was enriched in the first distillate composition. 
 
     
     
       6. The process of  claim 5  wherein said first bottoms composition comprises HFC-236cb essentially free of PFC-C318. 
     
     
       7. The process of  claim 5  wherein said second bottoms composition comprises PFC-C318 essentially free of HFC-236cb. 
     
     
       8. An azeotrope or near-azeotrope composition comprising from about 39.5 mole percent to about 59.5 mole percent hydrogen fluoride and from about 60.5 mole percent to about 40.5 mole percent PFC-C318. 
     
     
       9. The azeotrope or near-azeotrope composition of  claim 8 , wherein the vapor pressure of said composition is from about 1.81 psi (kPa) to about 565 psi (kPa) at a temperature of from about −50° C. to about 100° C. 
     
     
       10. The azeotrope or near-azeotrope composition of  claim 8  wherein said composition consists essentially of from about 39.5 mole percent to about 59.5 mole percent hydrogen fluoride and from about 60.5 mole percent to about 40.5 mole percent PFC- C318, wherein the vapor pressure is from about 1.81 psi (kPa) to about 565 psi (kPa) at a temperature of from about −50° C. to about 100° C.